Project description:<p>We describe four patients from two unrelated families of different ethnicities who had primary immunodeficiency predominantly manifesting as susceptibility to EBV-related diseases. We performed whole exome sequencing (P1 and P2 from family 1) or whole genome sequencing (P4 and both parents from family 2) in those two families and identified homozygous frameshift or in-frame deletions in CD70 in these patients which abolished either CD70 surface expression or binding to its counter structure CD27. Sanger sequencing identified the same homozygous <i>CD70</i> mutation in P3, which is not included in the dbGaP submission. Autosomal recessive CD70 deficiency is a novel cause of combined immunodeficiency and EBV-associated diseases, reminiscent of CD27 deficiency.</p>
Project description:We studied a case with suspected PIK3CD deficiency with a homozygous mutation in the patient in PIK3CD (c.1340-1 G>A). All other family members were tested and defined as carriers of the same mutation and are clinically healthy. The literature states that there is an AD but also an AR form of the disease (Immunodeficiency 14 A and B, respectively) linked to the gene. The clinical phenotype of the patient fits very well the description as LOF she suffers from severe, recurrent infections since infancy and has low overall IgG levels.